Annotation of src/usr.bin/ssh/ssh-ed25519-sk.c, Revision 1.11
1.11 ! djm 1: /* $OpenBSD: ssh-ed25519-sk.c,v 1.10 2022/10/28 00:39:29 djm Exp $ */
1.1 markus 2: /*
3: * Copyright (c) 2019 Markus Friedl. All rights reserved.
4: *
5: * Permission to use, copy, modify, and distribute this software for any
6: * purpose with or without fee is hereby granted, provided that the above
7: * copyright notice and this permission notice appear in all copies.
8: *
9: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16: */
1.4 djm 17:
18: /* #define DEBUG_SK 1 */
19:
1.1 markus 20: #define SSHKEY_INTERNAL
21: #include <sys/types.h>
22: #include <limits.h>
23:
24: #include "crypto_api.h"
25:
26: #include <string.h>
27: #include <stdarg.h>
28:
29: #include "log.h"
30: #include "sshbuf.h"
31: #include "sshkey.h"
32: #include "ssherr.h"
33: #include "ssh.h"
34: #include "digest.h"
35:
1.8 djm 36: /* Reuse some ED25519 internals */
37: extern struct sshkey_impl_funcs sshkey_ed25519_funcs;
38:
1.7 djm 39: static void
40: ssh_ed25519_sk_cleanup(struct sshkey *k)
41: {
1.8 djm 42: sshkey_sk_cleanup(k);
43: sshkey_ed25519_funcs.cleanup(k);
44: }
45:
46: static int
47: ssh_ed25519_sk_equal(const struct sshkey *a, const struct sshkey *b)
48: {
49: if (!sshkey_sk_fields_equal(a, b))
50: return 0;
51: if (!sshkey_ed25519_funcs.equal(a, b))
52: return 0;
53: return 1;
1.7 djm 54: }
55:
1.9 djm 56: static int
57: ssh_ed25519_sk_serialize_public(const struct sshkey *key, struct sshbuf *b,
58: const char *typename, enum sshkey_serialize_rep opts)
59: {
60: int r;
61:
62: if ((r = sshkey_ed25519_funcs.serialize_public(key, b,
63: typename, opts)) != 0)
64: return r;
65: if ((r = sshkey_serialize_sk(key, b)) != 0)
66: return r;
67:
68: return 0;
69: }
70:
1.11 ! djm 71: static int
! 72: ssh_ed25519_sk_copy_public(const struct sshkey *from, struct sshkey *to)
! 73: {
! 74: int r;
! 75:
! 76: if ((r = sshkey_ed25519_funcs.copy_public(from, to)) != 0)
! 77: return r;
! 78: if ((r = sshkey_copy_public_sk(from, to)) != 0)
! 79: return r;
! 80: return 0;
! 81: }
! 82:
1.1 markus 83: int
84: ssh_ed25519_sk_verify(const struct sshkey *key,
85: const u_char *signature, size_t signaturelen,
1.3 djm 86: const u_char *data, size_t datalen, u_int compat,
87: struct sshkey_sig_details **detailsp)
1.1 markus 88: {
89: struct sshbuf *b = NULL;
90: struct sshbuf *encoded = NULL;
91: char *ktype = NULL;
92: const u_char *sigblob;
93: const u_char *sm;
94: u_char *m = NULL;
95: u_char apphash[32];
96: u_char msghash[32];
97: u_char sig_flags;
98: u_int sig_counter;
99: size_t len;
100: unsigned long long smlen = 0, mlen = 0;
101: int r = SSH_ERR_INTERNAL_ERROR;
102: int ret;
1.3 djm 103: struct sshkey_sig_details *details = NULL;
104:
105: if (detailsp != NULL)
106: *detailsp = NULL;
1.1 markus 107:
108: if (key == NULL ||
109: sshkey_type_plain(key->type) != KEY_ED25519_SK ||
110: key->ed25519_pk == NULL ||
111: signature == NULL || signaturelen == 0)
112: return SSH_ERR_INVALID_ARGUMENT;
113:
114: if ((b = sshbuf_from(signature, signaturelen)) == NULL)
115: return SSH_ERR_ALLOC_FAIL;
116: if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
1.2 markus 117: sshbuf_get_string_direct(b, &sigblob, &len) != 0 ||
118: sshbuf_get_u8(b, &sig_flags) != 0 ||
119: sshbuf_get_u32(b, &sig_counter) != 0) {
1.1 markus 120: r = SSH_ERR_INVALID_FORMAT;
121: goto out;
122: }
1.4 djm 123: #ifdef DEBUG_SK
124: fprintf(stderr, "%s: data:\n", __func__);
125: /* sshbuf_dump_data(data, datalen, stderr); */
126: fprintf(stderr, "%s: sigblob:\n", __func__);
127: sshbuf_dump_data(sigblob, len, stderr);
128: fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n",
129: __func__, sig_flags, sig_counter);
130: #endif
1.1 markus 131: if (strcmp(sshkey_ssh_name_plain(key), ktype) != 0) {
132: r = SSH_ERR_KEY_TYPE_MISMATCH;
133: goto out;
134: }
135: if (sshbuf_len(b) != 0) {
136: r = SSH_ERR_UNEXPECTED_TRAILING_DATA;
137: goto out;
138: }
139: if (len > crypto_sign_ed25519_BYTES) {
140: r = SSH_ERR_INVALID_FORMAT;
141: goto out;
142: }
143: if (ssh_digest_memory(SSH_DIGEST_SHA256, key->sk_application,
144: strlen(key->sk_application), apphash, sizeof(apphash)) != 0 ||
145: ssh_digest_memory(SSH_DIGEST_SHA256, data, datalen,
146: msghash, sizeof(msghash)) != 0) {
147: r = SSH_ERR_INVALID_ARGUMENT;
148: goto out;
149: }
1.4 djm 150: #ifdef DEBUG_SK
151: fprintf(stderr, "%s: hashed application:\n", __func__);
152: sshbuf_dump_data(apphash, sizeof(apphash), stderr);
153: fprintf(stderr, "%s: hashed message:\n", __func__);
154: sshbuf_dump_data(msghash, sizeof(msghash), stderr);
155: #endif
1.3 djm 156: if ((details = calloc(1, sizeof(*details))) == NULL) {
157: r = SSH_ERR_ALLOC_FAIL;
158: goto out;
159: }
160: details->sk_counter = sig_counter;
161: details->sk_flags = sig_flags;
1.1 markus 162: if ((encoded = sshbuf_new()) == NULL) {
163: r = SSH_ERR_ALLOC_FAIL;
164: goto out;
165: }
166: if (sshbuf_put(encoded, sigblob, len) != 0 ||
167: sshbuf_put(encoded, apphash, sizeof(apphash)) != 0 ||
168: sshbuf_put_u8(encoded, sig_flags) != 0 ||
169: sshbuf_put_u32(encoded, sig_counter) != 0 ||
170: sshbuf_put(encoded, msghash, sizeof(msghash)) != 0) {
171: r = SSH_ERR_ALLOC_FAIL;
172: goto out;
173: }
1.4 djm 174: #ifdef DEBUG_SK
175: fprintf(stderr, "%s: signed buf:\n", __func__);
176: sshbuf_dump(encoded, stderr);
177: #endif
1.1 markus 178: sm = sshbuf_ptr(encoded);
179: smlen = sshbuf_len(encoded);
180: mlen = smlen;
181: if ((m = malloc(smlen)) == NULL) {
182: r = SSH_ERR_ALLOC_FAIL;
183: goto out;
184: }
185: if ((ret = crypto_sign_ed25519_open(m, &mlen, sm, smlen,
186: key->ed25519_pk)) != 0) {
1.6 djm 187: debug2_f("crypto_sign_ed25519_open failed: %d", ret);
1.1 markus 188: }
189: if (ret != 0 || mlen != smlen - len) {
190: r = SSH_ERR_SIGNATURE_INVALID;
191: goto out;
192: }
193: /* XXX compare 'm' and 'sm + len' ? */
194: /* success */
195: r = 0;
1.3 djm 196: if (detailsp != NULL) {
197: *detailsp = details;
198: details = NULL;
199: }
1.1 markus 200: out:
1.5 jsg 201: if (m != NULL)
202: freezero(m, smlen); /* NB mlen may be invalid if r != 0 */
1.3 djm 203: sshkey_sig_details_free(details);
1.1 markus 204: sshbuf_free(b);
205: sshbuf_free(encoded);
206: free(ktype);
207: return r;
208: }
1.7 djm 209:
210: static const struct sshkey_impl_funcs sshkey_ed25519_sk_funcs = {
211: /* .size = */ NULL,
212: /* .alloc = */ NULL,
213: /* .cleanup = */ ssh_ed25519_sk_cleanup,
1.8 djm 214: /* .equal = */ ssh_ed25519_sk_equal,
1.9 djm 215: /* .ssh_serialize_public = */ ssh_ed25519_sk_serialize_public,
1.10 djm 216: /* .generate = */ NULL,
1.11 ! djm 217: /* .copy_public = */ ssh_ed25519_sk_copy_public,
1.7 djm 218: };
219:
220: const struct sshkey_impl sshkey_ed25519_sk_impl = {
221: /* .name = */ "sk-ssh-ed25519@openssh.com",
222: /* .shortname = */ "ED25519-SK",
223: /* .sigalg = */ NULL,
224: /* .type = */ KEY_ED25519_SK,
225: /* .nid = */ 0,
226: /* .cert = */ 0,
227: /* .sigonly = */ 0,
228: /* .keybits = */ 256,
229: /* .funcs = */ &sshkey_ed25519_sk_funcs,
230: };
231:
232: const struct sshkey_impl sshkey_ed25519_sk_cert_impl = {
233: /* .name = */ "sk-ssh-ed25519-cert-v01@openssh.com",
234: /* .shortname = */ "ED25519-SK-CERT",
235: /* .sigalg = */ NULL,
236: /* .type = */ KEY_ED25519_SK_CERT,
237: /* .nid = */ 0,
238: /* .cert = */ 1,
239: /* .sigonly = */ 0,
240: /* .keybits = */ 256,
241: /* .funcs = */ &sshkey_ed25519_sk_funcs,
242: };
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